The present invention relates to a vacuum cleaner of the type comprising a motor-driven fan unit mounted in a casing provided with a discharge aperture which, via an internal duct, communicates with the outlet of the fan unit.
Technical progress made within the field of electromotors have resulted in that normal standard motors - which, inter alia, for economical reasons are preferred in vacuum cleaners - are able to operate at rather high temperatures which, in itself, is advantageous discharge it is then possible to employ motors having small dimensions in relation to their performance and consequently the suction effect of the fan driven by the motor. However, in a vacuum cleaner, a high motor temperature results in a correspondingly high temperature of the filtered air discharged from the vacuum cleaner. The high air temperature can in itself be unpleasant for the person operating the vacuum cleaner who easily gets in the way of the hot air stream, but it has also the disadvantage that it causes a heating of the wall of the vacuum cleaner casing around the dicharge aperture, which wall can become so hot that the operator runs the risk of getting burned when touching it. This is particularly the case when the casing wall is made of metal which often is most expedient with a view to the mechanical strength and/or to the manufacturing costs.